Hey thehooligans,
Thanks for reaching out! In order for the set up above to work, you will need to have a secondary IP enabled on the Cisco modem. Once that is enabled, port 1 and 2 will give out separate IP addresses for your two 3rd party routers. To have a secondary IP enabled, you will need to reach out to our customer support team members. Let me know if you have any other questions.
Cheers,
Tony | Community Mod.